Gas discharge display and method for producing the same

ABSTRACT

A gas discharge display apparatus, in which a plurality of cells filled with a discharge gas are arranged in a matrix pattern in a space between first and second substrates placed in opposition to each other, and at least one pair of display electrodes are arranged on a surface of the first substrate facing the second substrate so as to span the plurality of cells. Here, each pair of display electrodes includes two extension parts that extend lengthwise along the matrix. A plurality of inner projections are electrically connected to each extension part, and protrude toward the other extension part. At least two connectors are arranged, with a fixed interval therebetween, between the two extension parts, each connector electrically connecting at least two inner projections provided for a same extension part.

TECHNICAL FIELD

The present invention relates to a gas discharge display apparatushaving a gas discharge panel, such as a plasma display panel, and amanufacturing method for the same.

BACKGROUND ART

Large screen display devices with high picture quality, such as thatproduced by high definition television (HDTV), have recently become thefocus of much expectation. As a result, research and development ofdisplay devices such as cathode ray tubes (CRTs), liquid crystaldisplays (LCDs), and plasma display panels (PDPs) is taking place. Thesevarious types of display devices each have the followingcharacteristics.

CRTs have excellent resolution and picture quality, and are widely usedin conventional televisions and the like. The large increases in depthand weight required to produce a large screen CRT, however, areproblematic, and solving this difficulty is crucial for the developmentof such CRTs. Due to this problem, it is believed to be difficult toproduce a CRT with a large screen of more than 40 inches.

LCDS, on the other hand, use less electricity than CRTs, and areextremely light and slim. Nowadays, LCDs are being increasingly used ascomputer monitors. However, typical LCD, which uses a thin filmtransistor (TFT) screen or similar, has an extremely intricatestructure, and so manufacture of such a device requires a plurality ofcomplicated processes. These processes become increasingly complex asscreen size increases, with the result that manufacturing yielddecreases as screen size grows larger. This means that it is currentlyconsidered difficult to manufacture an LCD with a screen of more than 30inches.

In contrast to CRTs and LCDs, PDPs are gas discharge panel displayapparatuses that have the advantage of being able to realize alightweight display with a large screen. Therefore, in the currentsearch for the next generation of displays, research and development oflarge screen PDPs is being pursued particularly aggressively, andproducts with screens of more than 60 inches are being developed.

In a basic PDP structure, a glass substrate, on which a plurality ofpairs of display electrodes and a plurality of barrier ribs are arrangedin a stripe formation, is placed in opposition to another glasssubstrate. Phosphors in each of the three colors red, green and blue areapplied hermetically to the spaces between the barrier ribs. The twoglass substrates are then sealed together so as to be airtight, and adischarge gas enclosed in the discharge spaces between the barrier ribsand the two glass substrates. Discharge from the plurality of pairs ofdisplay electrodes causes the discharge gas to generate ultraviolet (UV)light, and this in turn causes the phosphors to emit light. Here, FIG.13A is a diagonal view of a pair of conventional PDP electrodes 22 and23 arranged on top of a front glass substrate 21, and FIG. 13B is anaerial view of the pair of electrodes 22 and 23 looking down in adirection z. The electrodes 22 and 23 shown in the drawings are formedfrom strip-shaped transparent electrodes 220 and 230, on which metal buslines (bus electrodes) 221 and 231 are overlaid. A numerical reference340 indicates cells for image display divided by neighboring barrierribs 30, so that, for example, cells 340 having phosphor layers in thecolors red, green and blue are arranged in parallel with the xdirection, forming pixels for achieving a color display.

PDPs such as this one can be divided into two types, direct current (DC)and alternating current (AC), according to the driving method used. ACPDPs are thought to be more suitable for producing a large screendevice, and thus are the most common type of PDP.

However, current demand is for electronic products that limitconsumption of electricity to as low a level as possible. In thisclimate, the need for PDPs that can be driven using a small amount ofelectricity is growing. In particular, the current trend towarddevelopment of large-screened and high-resolution PDPs has led to anincrease in the electrical consumption of such PDPs, and so there is anincreasing demand for energy-saving techniques. It is hoped that suchtechniques will reduce the electrical consumption of PDPs.

However, merely carrying out strategies for reducing the electricalconsumption of a PDP causes the scale of discharge generated between theplurality of pairs of display electrodes to be reduced, and satisfactorylight emission becomes unachievable. As a result, it is necessary tomaintain satisfactory display quality (in other words satisfactoryluminous efficiency) while limiting electrical consumption. Ifinsufficient light is emitted, the display quality of the PDP will bereduced, so merely decreasing the electrical consumption of the PDPcannot be said to be a valid strategy for increasing luminousefficiency.

Research is being conducted into a method for improving luminousefficiency by, for example, raising the efficiency with which phosphorsconvert ultraviolet light into visible light. However, at this point intime no noticeable improvements have been observed by using this method,and there is still room for further research to be conducted.

The above problem is not confined to a gas discharge panel such as a PDP(that emits light by generating a discharge within a glass containerfilled with discharge gas), and also exists, for example, in other gasdischarge display apparatuses that provide a gas discharge device otherthan a PDP.

Currently, it is thought to be extremely difficult to preserve theappropriate luminous efficiency in this kind of gas discharge displayapparatus.

DISCLOSURE OF THE INVENTION

The present invention is designed to overcome the above problems, andhas as its object the provision of a gas discharge display apparatuscapable of preserving appropriate luminous efficiency, and by this meansachieving a lower level of electrical consumption than is conventionallypossible, while preserving the scale of discharge required to achievesatisfactory display quality, and of a manufacturing method for thesame.

The above object is realized by a gas discharge display panel in which aplurality of cells filled with a discharge gas are arranged in a matrixpattern in a space between first and second substrates placed inopposition to each other. At least one pair of display electrodes arearranged on a surface of the first substrate facing the second substrateso as to span the plurality of cells. Each pair of display electrodesincludes two extension parts that extend lengthwise along the matrix, aplurality of inner projections electrically connected to each extensionpart, and protruding toward the other extension part, and at least twoconnectors arranged, keeping a fixed interval therebetween, between thetwo extension parts. Each connector electrically connects at least twoinner projections provided for a same extension part.

In the present invention, display electrodes are formed by combininginner projections and connectors, so the discharge generated in the gapbetween a pair of display electrodes is gradually expanded by the innerprojections and the connectors connected to the inner projections. Inparticular, since the connectors and inner projections are electricallyconnected, satisfactory expansion of discharge can be achieved along thedisplay electrodes.

Furthermore, a plurality of apertures are formed between the extensionparts and the plurality of connectors. Naturally a charge is notaccumulated in these apertures, and so an electric charge accumulated onthe display electrodes is reduced to less than in the prior art whendischarge is started by driving the gas discharge display apparatus.Once discharge has started, it also expands by diffusing to theapertures, and so a satisfactory level of discharge can be achieved inspite of the presence of the apertures.

Such characteristics enable the gas discharge display apparatus of thepresent invention to reduce the charge accumulated on the displayelectrodes, and restrict power consumption, as well as maintaining adisplay quality that is at least equivalent to that of a conventionaldevice. In other words, the present invention effectively reduces thesurface area of the display electrodes in the display unit (electriccapacity), reducing excess power consumption, and realizing a gasdischarge display apparatus with superior luminous efficiency.

References such as Japanese Laid Open Patent H8-250029, and U.S. Pat.No. 5,587,624 disclose an example of a technique for providing aplurality of projections for the display electrodes, thereby improvingluminous efficiency and the like.

However, these references do not disclose a technique like the onedescribed in the present invention for providing connectors toelectrically connect the at least two inner projections, and sinceprojections are formed independently, alignment is difficult to achieve.The present invention, provides the display electrodes with connectors,achieving a superior effect by avoiding both the large increases inmanufacturing costs caused by variations in accuracy duringmanufacturing, and deterioration in image uniformity.

An actual example of the gas discharge display apparatus of the presentinvention may be a PDP or similar device. PDPs with larger screens arecurrently being developed, and this leads to increases in powerconsumption. Consequently, the present invention is particularlyeffective when applied to a PDP.

The present invention may arrange a plurality of connectors on eachextension part.

Furthermore, the inner projections and the connectors may bemanufactured of a transparent electrode material, and the extensionparts of a metal material. Here, the extension parts are bus lines.Since the transparent electrode material has a lower electric resistancethan the metal material, if this construction is applied in the presentinvention, power consumption is likely to be further reduced.

Furthermore, the present invention, outer projections may extend from aside of a bus line in an opposite direction to inner projections. Whensuch a technique is used, in addition to the above effects, dischargeexpands from the bus line outward, and superior luminous efficiency canbe achieved.

In addition, when a layer is formed so as to cover the at least one pairof display electrodes, areas of the layer corresponding to a minimumdischarge gap between a pair of display electrodes may be formed ofmagnesium oxide, and other parts of the layer from a material with alower electron emission yield than magnesium oxide (for examplealuminum). This enables discharge to be generated more easily in aninitial discharge period when the gas discharge display apparatus isdriven.

A BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a diagonal view of part of a PDP in a first embodiment of theinvention;

FIG. 2 is an outline drawing of a PDP panel driver, display electrodesand the like in the first embodiment;

FIG. 3 shows a drive process performed by the panel driver in the firstembodiment;

FIG. 4 is an aerial view showing display electrodes in the PDP of thefirst embodiment;

FIG. 5 is an aerial view showing display electrodes in the PDP of asecond embodiment;

FIG. 6 is an aerial view showing display electrodes in the PDP of athird embodiment;

FIG. 7 is an aerial view showing display electrodes in the PDP of afourth embodiment;

FIG. 8 is an aerial view showing display electrodes in the PDP of afifth embodiment;

FIG. 9 is an aerial view showing an modification of the displayelectrodes in the fifth embodiment;

FIG. 10 is a partial cross-section of a PDP in a sixth embodiment;

FIG. 11 is an aerial view of the display electrodes in the firstembodiment on which black matrix processing has been performed;

FIG. 12 shows a structure of a gas discharge device that is an exampleapplication of the present invention;

FIG. 12A is a diagonal view of the entire gas discharge device;

FIG. 12B shows a structure of a discharge electrode in a gas dischargedevice;

FIG. 13 is an aerial view showing display electrodes in a conventionalPDP;

FIG. 13A is a partial diagonal view showing conventional displayelectrodes; and

FIG. 13B is an aerial view showing conventional display electrodes.

PREFERRED EMBODIMENTS OF THE INVENTION 1. Structure of Gas DisplayApparatus

1-1. First Embodiment

FIG. 1 is a diagonal view in cross-section showing part of a basicstructure for a panel 2, that is for a AC surface discharge PDP that isone example of a gas discharge display apparatus in a first embodiment.In the drawing, an z direction corresponds to the depth of the PDP, andan xy plane to a flat surface parallel to the panel surface of the PDP.The directions x, y, and z are identical in all of the FIGS. 1 to 13explained hereafter. The structure of the PDP can be broadly dividedinto the panel 2, and a panel driver 1 (explained hereafter).

The panel 2 is formed from a front substrate 20 and a back substrate 26,arranged with their respective main surfaces in opposition.

A pair of display electrodes 22 and 23 (X electrode 22, and Y electrode23) are formed parallel with the x direction on one surface of a frontglass plate 21 that forms the base for the front substrate 20. Surfacedischarge is generated between the pair of electrodes 22, and 23. Thedetailed structure of the display electrodes 22, and 23 is explainedlater in this description.

The entire surface of the front glass plate 21, on which the displayelectrodes 22 and 23 have been arranged, is coated with a dielectriclayer 24. Then, a protective layer 25 is coated on top of the dielectriclayer 24.

A plurality of address electrodes 28 are arranged at fixed intervals ina stripe formation parallel with the y direction, on one surface of aback glass substrate 27 that forms the base for the back substrate 26.Then the entire surface of the back glass substrate 27 is coated with adielectric layer 29 so as to embed the address electrodes 28. Barrierribs 30 are arranged on top of the dielectric layer 29 in the gapsbetween neighboring address electrodes 38. Then phosphor layers 31, 32,and 33, which correspond respectively to the three colors red (R), green(G), and blue (B), are formed in turn on the side walls of neighboringbarrier ribs 30 and the surface of the dielectric layer 29 therebetween.These R, G, and B phosphor layers are arranged in order, parallel withthe x direction, enabling a color display to be formed.

A front substrate 20 and back substrate 26 having the above structureare placed in opposition so that the address electrodes 28 areorthogonal to the display electrodes 22 and 23. Then, the perimeters ofthe front and back substrates 20 and 26 are brought into contact andsealed. Following this, a discharge gas (filler gas) formed of one ormore inert gases such as He, Xe, and Ne, is introduced into the spacebetween the front and back substrates 20 and 26 at a certain pressure(conventionally this is in a range of around 4×10⁴ to 8×10⁴ Pa).Following this, the gaps between neighboring barrier ribs 30 becomedischarge spaces 38, and an area in which a pair of neighboringelectrodes 22 and 23 and an address electrode 28 intersect orthogonallywith a discharge space 38 therebetween, corresponds to an image displaycell 340 (shown in FIG. 2 onward). Then, when the PDP is driven by thepanel driver 1, vacuum ultraviolet light (a resonance line havingcentral wavelengths of 147 nm and 173 nm) is generated from dischargeproduced between the address electrode 28, and one of the displayelectrodes 22 and 23 (in this embodiment, the X electrode 22), andbetween the pair of display electrodes 22 and 23, and phosphor layers 31to 33 emit light to display an image. Note that conventionally the Xelectrode 22 is referred to as a scan electrode, and the Y electrode 23as a sustain electrode.

Note that the inside of discharge spaces 38 is exhausted via a tip tube(not shown) attached to the back substrate 26, and then discharge gas isintroduced at a certain pressure (in the PDP of the present invention2.6×10⁵ Pa). When the pressure of the discharge gas is higher thanatmospheric pressure, the front and back substrates 20 and 26 shouldpreferably be connected via the tops of the barrier ribs 30.

Here, FIG. 2 is an outline drawing of the front substrate 21 on whichthe display electrodes 22 and 23 have been arranged, and the paneldriver 1 that is connected to the display electrodes 22 and 23 and theaddress electrodes 28.

The panel driver 1 shown in the drawing has a structure well-known inthe art, and includes, for example, a data driver 101 connected toaddress electrodes 28, a sustain driver 102 connected to Y electrodes22, a scan driver 103 connected to X electrodes 23, and a drive circuit100 that controls the drivers 101 to 103.

The drivers 101 to 103 control the passage of current respectively toconnected electrodes 22, 23, 28 and the like, the drive circuit 100controls the operations of the drivers 101 to 103, and enables an imageto be displayed accurately.

The drive circuit 100 has an internal memory that temporarily storesimage data output from outside of the PDP, and a plurality ofinternalized circuits that successively read pieces of the stored imagedata and perform image processing such as gamma correction.

Next, the general driving procedure performed by the panel driver 1,including the above components 100 to 104, to drive the PDP is explainedwith reference to FIG. 3.

First, an initializing pulse is applied to the X electrodes 22 by thescan driver 103 in the panel driver 1, thereby initializing a charge(wall charge) inside the cells 340.

Next, the panel driver 1 uses the scan driver 103 and the data driver101 respectively to simultaneously apply (1) a scan pulse to an Xelectrode 22 that is first from the top of the flat surface of the panel1, and (2) a write pulse to an address electrode 28 corresponding to adisplay cell 340, generating a write discharge, and accumulating a wallcharge on the surface of the dielectric layer 24.

Next, the panel driver 1 simultaneously applies a scan pulse to thesecond X electrode 22, and a write pulse to an address electrodecorresponding to a display cell 340, generating a write discharge andaccumulating a wall charge on the surface of the dielectric layer 24.

The panel driver 1 applies successive scan pulses to accumulate wallcharges on parts of the surface of the dielectric layer 24 correspondingto each display cell 340 in turn, thereby writing a one-screen latentimage.

Next, in order to generate a sustain discharge (surface discharge), thepanel driver 1 grounds the address electrodes 28, and uses the scandriver 103 and the sustain driver 102 to apply alternating sustainpulses between a pair of display electrodes 22 and 23. This enables adischarge to be generated when the potential of the surface of thedielectric layer 24 in cells 340 in which a discharge has beenaccumulated exceeds a discharge firing voltage. This discharge (in otherwords surface discharge) is sustained for a period during which thesustain pulses are applied (the discharge sustain period shown in FIG.3).

Following this, the panel driver 1 applies a narrow pulse to the Xelectrodes 22 via the scan driver 103, generating an imperfect dischargein order to reduce the wall charge, and erase the screen (erase period).By repeating these operations, the panel driver 1 displays a screen onthe panel 2.

This completes the explanation of the overall structure of the paneldriver 1 and the panel 2 of the present PDP, and of the generaloperations thereof. The present invention is mainly characterized by astructure focusing on the display electrodes 22 and 23.

FIG. 4 is a partial aerial view of display electrodes 22 and 23 formedon the front panel 21 of the PDP, seen from the z direction (the depthof the PDP). In the drawing, two dashed lines running parallel to the ydirection indicate a cell pitch (360 μm) between two neighboring barrierribs 30 in the x direction. Furthermore, the distance between parallelchain lines on either side of each dashed line corresponds to thethickness of the barrier ribs 30.

Note that FIG. 4, and the following drawings FIGS. 5 to 9 and FIG. 11omit the address electrodes 28 for the sake of simplicity.

A pair of display electrodes 22 and 23 are mainly constructed fromtransparent electrodes 220 and 230, and bus lines 221 and 231. Thetransparent electrodes 220 and 230 are formed of indium tin oxide (ITO),and the bus lines 221 and 231 from Cr—Cu—Cr or mainly from Ag (in thisdescription Ag is used).

The transparent electrodes 220 and 230 are formed from bases 2201 and2301, inner projections 2202 a and 2302 a, and connectors 2203 and 2303.

The bases 2201 and 2301 are strips extending in the x direction (40 μmin the y direction×4 μm in the z direction). The bus lines 221 and 231are strips (30 μm× in the y direction×4 μm in the z direction) laminatedalong the tops of the bases 2201 and 2301 so as to be electricallyconnected.

The inner projections 2202 a and 2302 a are narrow bands 40 μm in the xdirection×80 μm in the y direction×0.5 μm in the z direction, extendingfrom the bases 2201 and 2301 in gaps between each pair of displayelectrodes 22 and 23, and arranged a fixed distance (50 μm) apart in thex direction. In the first embodiment of this invention, the innerprojections 2202 a and 2302 a are arranged four to each cell pitch (atotal of eight for a pair of display electrodes 22 and 23).

The connectors 2203 and 2303 are strips (30 μm in the y direction×0.5 μmin the z direction) stretching in the x direction, and connecting theends of the inner projections 2202 a and 2302 a.

By forming the transparent electrodes 220 and 230 in this way, aplurality of virtually rectangular (50 μm in the x direction×50 μm inthe y direction) apertures 2204 and 2304 are lined up along the xdirection in each cell pitch of the transparent electrodes 220 and 230,forming an array pattern.

Note that in FIG. 4, a minimum gap between a pair of display electrodes22 and 23, in other words a discharge gap D₁ between connectors 2203 and2303, is 40 μm, a discharge gap D₂ between neighboring bus lines 221 and231 is 210 μm, and a maximum discharge gap D₃ between a pair of displayelectrodes 22 and 23 is 280 μm. Furthermore, a gap between neighboringpairs of display electrodes 22 and 23 in the y direction is set at 400μm to prevent the generation of crosstalk and the like, and cell pitchin the y direction is 1080 μm. In FIG. 4, the characteristics of theshape of the transparent electrodes 220 and 230 in the first embodimentof the present invention are illustrated in a simplified manner, byshowing the widths of and gaps between the bases 2201 and 2301, theinner projections 2202 a and 2302 a and the like as narrower than theyactually are.

Display electrodes 22 and 23 having this kind of structure aremanufactured taking the following points into account.

The ITO or similar used to form the transparent electrodes 220 and 230has a higher electrical resistance than the metal (a composite formedmainly from Ag or similar) used to form the bus lines 221 and 231.

Here, all of the electric power supplied to the transparent electrodes220 and 230 from outside may not necessarily be used as discharge forgenerating ultraviolet light, and as discharge itself, and may bewastefully consumed by being accumulated as unnecessary charges on thetransparent electrodes 220 and 230.

Furthermore, even if transparent electrodes are used in the vicinity ofthe areas where the barrier ribs 30 and the transparent electrodes 220and 230 intersect (in other words, areas of the transparent electrodes220 and 230 near to the barrier ribs 30), little direct contribution tolight emission is made and so this is likely to lead to theaforementioned excess electric consumption.

Here, the present invention reduces the parts of the transparentelectrodes that generate excess electric consumption in a conventionalPDP. Accordingly, the transparent electrodes 220 and 230 in the firstembodiment have a well-balanced design that restricts consumption ofelectricity by having a smaller surface area than in the prior art,thereby preventing the accumulation of excess charges, and maintains asatisfactory level of surface discharge (in particular the amount thatdischarge extends in the x direction).

Furthermore, in the first embodiment, the discharge gaps for a pair ofdisplay electrodes 22 and 23 are formed in the following way in order toachieve satisfactory luminous efficiency. Firstly, the discharge gap D₁between the inner projections 2202 a and 2302 a is set based onPaschen's law, which is wellknown in the art. In other words, when adischarge gas pressure is P, and a discharge gap d, a Paschen curveshowing a relationship between a product of Pd and a discharge firingvoltage is used to set the discharge gap D₁ at approximately 40 μm. Thisgap width is one at which the discharge firing voltage in relation tothe above discharge gas pressure P (2.6×10⁵ Pa) is just slightly morethan a minimum value, taking into account variations in individual PDPscreated during production. In addition, based on the same Paschen curve,the gap D₂ between the bus lines 221 and 231 is set at a value at whichthe minimum discharge sustain voltage is in a vicinity of a minimumluminous efficiency value. The maximum discharge gap D₃ between a pairof display electrodes 22 and 23 is set so as to obtain a satisfactorylevel of surface discharge.

Note that the shape of the Paschen curve varies according to the type ofdischarge gas used, and so the values of D₁ to D₃ are characterized bydependency on the Paschen curve for each discharge gas. Therefore, whenD₁ to D₃ are set, the most appropriate values for the conditionsconcerned should be investigated by reference to the appropriate Paschencurve.

Furthermore, as in the first embodiment, the plurality of innerprojections 2202 a and 2302 a are connected electrically by theconnectors 2203 and 2203, so there will be little impact on dischargeeven if a manufacturing error places the inner projections 2202 a and2302 a slightly out of position.

During the initial part of a discharge sustain period when a PDP havingthe above structure is driven, a sustain pulse is applied to a pair ofdisplay electrodes 22 and 23, and surface discharge starts in dischargegaps D₁, in other words at the ends of the inner projections 2202 a and2302 a, that are set at the optimum for the firing voltage as defined byPaschen's law. Since discharge gaps D₁ are about 40 μm, that is narrowerthan conventional gaps, the voltage required for starting discharge(discharge firing voltage) is less than in a PDP that is not providedwith inner projections, and a satisfactory discharge can be producedwhile reducing electrical consumption.

Once discharge has started in the PDP of this invention, it spreads outin the x and y directions (across the panel surface) during thedischarge sustain period, and the area of display electrodes 22 and 23that contributes to this discharge is enlarged through provision of thebus lines 221 and 231. A particular characteristic of this invention isthe placement of the connectors 2203 and 2303, which enables enlargementof discharge in the x direction to be achieved satisfactorily. In otherwords, the present invention uses the fact that the scale of dischargeis enlarged over an area larger than the areas of the electrodes onwhich a charge is originally accumulated. Consequently, even if thesurface area of the transparent electrodes 220 and 230 is reduced byproviding the apertures 2204 and 2304, discharge, once initialized, alsooccurs in the apertures 2204 and 2304, enabling the scale of dischargeto be maintained at a satisfactory level.

Discharge generated in the discharge gap D₁ spreads out over the maximumdischarge gap D₃ between outer projections 222 b and 232 b, enablingdischarge to occur over a wide area. Therefore, the invention of thefirst embodiment restricts excess electrical consumption, and maintainsa satisfactory level of surface discharge. As a result, a PDP with asuperior balance between light emission and electric consumption, inother words luminous efficiency, can be achieved.

Here, the cell pitch of the inner projections need not be limited to 4,and a different cell pitch may be used. Furthermore, the dimensions ofthe inner projections 2202 a and 2303 a, the connectors 2203 and 2303and the like may be adjusted as appropriate according to cell size.However, if the connectors 2203 and 2303 or similar are too narrow,electrical resistance will increase, and excess electrical consumptionmay be generated through Joule heat loss and the like. Consequently, itis desirable to set these dimensions after experiments have beenperformed to ascertain the balance between electrical consumption andluminous efficiency. Furthermore, the dimensions of the transparentelectrodes 220 and 230 in each of the following embodiments may bechanged based on similar conditions.

The following is an explanation of the other embodiments. Note that onlythe particular characteristics of each embodiment are described to avoidduplicate explanation.

1-2 Second Embodiment

In the first embodiment the bases 2201 and 2301 have transparentelectrodes 220 and 230, but the bases 2201 and 2301 may be omitted, andan improvement where the electrical consumption of the transparentelectrodes 220 and 230 is further reduced in areas where the bases 2201and 2301 and the bus lines 221 and 231 overlap achieved.

Here, the overhead view of a pair of display electrodes 22 and 23 inFIG. 5 shows the characteristic of the second embodiment that achievesthe above improvement. In the second embodiment, in addition to theabove improvement, outer projections 2202 b and 2302 b (each 40 μm inthe x direction, 30 μm in the y direction, and 0.5 μm in the ydirection), which are extensions of the inner projections 2202 a and2302 a, are arranged so as to extend outwards from the gaps between thepair of display electrodes 22 and 23. In other words, in the secondembodiment, projections 2202 and 2302 (40 μm in the x direction, 30 μmin the y direction, and 0.5 μm in the y direction), formed in one piecefrom the inner projections 2202 a and 2302 a and the outer projections2202 b and 2302 b, intersect with the bus lines 221 and 231, and theends of inner projections 2202 a and 2302 a connect with the connectors2203 and 2303. As a result, the discharge gaps D₁, D₂, and D₃ are set at40 μm, 200 μm, and 320 μm respectively.

Note that cell pitch in the x and y directions is set at 360 μm and 1080μm respectively.

In addition to the effects produced in the first embodiment, the PDP ofthe second embodiment having the structure described above can beexpected to achieve further improvements in power saving, since itreduces the excess electrical consumption caused by accumulation ofcharges when a PDP having bases 2201 and 2301 is driven during thedischarge sustain period. Furthermore, the discharge generated spreadsout from the bus lines 221 and 231 to the outer projections 2202 b and2302 b, enlarging the scale of surface discharge generated by acorresponding amount, so that surface discharge with a satisfactoryluminous efficiency can be achieved.

Note that only one of the outer projections 2202 b and 2303 b may beprovided, but in order to ensure the satisfactory scale of surfacedischarge described above, both the outer projections 2202 b and 2302 bshould preferably be provided.

1-3 Third Embodiment

The transparent electrodes 220 and 230 in the third embodiment are basedon those in the second embodiment, and are additionally provided with aplurality of connectors. These are first connectors 2203 a and 2303 a,and second connectors 2203 b and 2303 b, which are structured so thatprojections 2204 and 2304 are connected by the first and secondconnectors 2203 a to 2203 b, as shown in the aerial view of a pair ofdisplay electrodes 22 and 23 in FIG. 6.

To be more specific, the bases 2201 and 2301 provided in the firstembodiment are omitted, the projections 2202 and 2302 arranged tointersect with the bus lines 221 and 231, and the inner and outerprojections 2202 a, 2302 a, 2202 b, and 2302 b are provided. In additionto this the first connectors 2203 a and 2303 a and the second connectors2203 b and 2303 b are arranged in parallel with the x direction. Thismeans that, in the third embodiment, the transparent electrodes 220 and230 are formed in an array pattern in which a plurality of apertures2204 and 2304 are arranged in a two-level matrix in the x and ydirections.

The dimensions of each part included in the transparent electrodes 220and 230 are, for example, as those shown below. Note that in FIG. 4, inorder to make the shape of the transparent electrodes 220 and 230 easierto understand, the apertures 2204 and 2304 and the like have a shapethat is. slightly different from their actual shape.

First connectors 2203 a, 2303 a, second connectors 2203 b, 2303 b: 20 μmin the y direction×0.5 μm in the z direction.

Apertures 2204, 2304: 50 μm in the x direction×10 μm in the y direction.

Inner projections 2202 a, 2302 a: 40 μm in the x direction×80 μm in they direction×0.5 μm in the z direction.

Outer projection 2202 b, 2302 b: 40 μm in the x direction×30 μm in the ydirection×0.5 μm in the z direction.

Cell pitch in x and y directions: 360 μm and 1080 μm respectively.

Discharge gaps D₁, D₂, D₃: 40 μm, 200 μm and 320 μm respectively.

In addition to the effects produced in the second embodiment, the PDP ofthe third embodiment having the structure described above can beexpected to further improve the spread of surface discharge in the xdirection from when the PDP is driven at the start of the dischargesustain period onward. This is achieved by providing a total of fourconnectors (first connectors 2203 a and 2303 a, and second connectors2203 b and 2303 b).

1-4 Fourth Embodiment

The PDP in the fourth embodiment has broadly the same structure as thatin the third embodiment, as is shown in the aerial view of a pair ofdisplay electrodes 22 and 23 in FIG. 7. However, this PDP ischaracterized by having the ends of inner projections 2202 a and 2302 aaligned with the connectors (in the drawing with the second connectors2203 b and 2303 b).

In addition to the effects produced in the third embodiment, the PDP ofthe fourth embodiment having the structure described above can generatea uniform discharge and generate discharge more easily when the PDP isdriven at the start of the sustain discharge period. This is achieveddue to the fact that a minimum discharge gap D₁ applicable for dischargeinitialization extends uniformly in the x direction.

1-5 Fifth Embodiment

In the fifth embodiment, transparent electrodes 220 and 230 are providedwith first to third connectors 2203 a to 2203 c and 2303 a to 2303 c inthree lines parallel to the x direction, as shown in the aerial view ofa pair of display electrodes 22 and 23 in FIG. 8. The third connectors2203 c and 2303 c connect the ends of inner projections 2203 a and 2303a. The size of apertures 2204 and 2304, which are formed in an arraypattern having three levels along the y direction, is set so thatapertures 2204 and 2304 in levels further from the gap between the pairof display electrodes 22 and 23 are smaller. The width of innerprojections 2202 a and 2302 a in the x direction increases in levelsnearer to the gap between the pair of display electrodes 22 and 23. Theshape of such transparent electrodes 220 and 230 is set with the aim ofincreasing the accumulation of electric charge across discharge gap D₃at points nearer to the gap D₁.

In the PDP of the fifth embodiment having this structure, a satisfactorydischarge can be started by accumulating a sufficient charge. This isachieved due to the fact that a charge can be accumulated most easily inthe vicinity of the minimum gap D₁ between a pair of display electrodes23 and 23 when the PDP is driven at the start of the discharge period.Following this, once surface discharge has stabilized, discharge spreadsout across to parts of gaps D₂ and D₃₁ which have less charge than D₁,so that discharge is generated across a wide area. By accumulating anappropriate amount of charge on the transparent electrodes 220 and 230according to the amount required, consumption of excess power can beavoided, and a PDP with an excellent power consumption/luminousefficiency balance can be achieved.

Note that FIG. 8 shows an example in which the size of the apertures2204 and 2304 is gradated, but a similar effect may also be achieved bykeeping the size of the apertures 2204 and 2304 uniform, and increasingthe pitch between neighboring apertures 2204 and 2304 (in other wordsthe width of inner projections 2203 a and 2303 a in the x direction)that are nearer to the gap D₁.

Furthermore, the fifth embodiment describes a structure in which chargescan be more easily accumulated in areas of the transparent electrodes220 and 230 in the vicinity of the minimum discharge gap D₁, and inwhich the amount of charge accumulated is reduced moving out across themaximum discharge gap D₃. However, the invention need not be limited tothis structure, and the amount of charge accumulated on a pair ofdisplay electrodes 22 and 23 may be set in a different way. For example,the position of apertures 2204 and 2304 arranged in the three-levelarray pattern in FIG. 8 may be altered so that the apertures 2204 and2304 are arranged in the size order large→small→medium moving from theminimum discharge gap D₁ toward the bus lines 221 and 231. As a result,the amount of charge accumulated on the transparent electrodes 220 and230 is small→large→medium, moving in the same direction. By using such astructure, an effect can be obtained such that a large number ofphosphors can be excited in areas having a high accumulation ofdischarge, that is areas with high energy efficiency, during a dischargeprocess in which discharge spreads out from the discharge gaps towardthe bus lines 221 and 231.

1-6 Sixth Embodiment

The structure of a pair of display electrodes 22 and 23 in the sixthembodiment is broadly the same as that in the first embodiment (see FIG.4), the sixth embodiment being characterized by the structure of theprotective layer 25. FIG. 10 is a partial cross-section across the depthof the PDP (z direction).

Here, a protective layer 251 of magnesium oxide (MgO) is formed on topof the dielectric layer 24 that covers the whole of the front glasssubstrate 21, over areas that correspond to the inner projections 2202 aand 2302 a (in FIG. 10 these areas are directly above the innerprojections 2202 a and 2302 a), and a protective layer 252 of aluminum(Al₂O₃) is formed over remaining areas.

In a PDP with this kind of structure, the magnesium oxide has a higherrate of electron emission than the aluminum. As a result, at the startof the discharge sustain period when the PDP is driven, discharge can begenerated more easily in the minimum discharge gap D₁, the dischargefiring voltage is restricted, and electric consumption when discharge isstarted is also restricted. Following this, the whole of cells 340 arefilled with electrons. Once sustain discharge begins, discharge is alsogenerated by the aluminum protective layer 252, but this has littleimpact on light emission, restricting excess electron emission, andresults in a reduction in the amount of electric current. The lightemitting area at this time is satisfactorily maintained, as in the otherembodiments.

Note, that the material with a low electron emission yield used for theprotective layer need not be limited to aluminum, and other materialsmay be used. Furthermore, the shape of the display electrodes need notbe limited to that described in the previous embodiments, and may bechanged as appropriate in so far as is possible. In addition, the methodfor arranging the magnesium oxide protective layer 251 need not belimited to that described above, where it is arranged in correspondencewith the inner projections 2202 a and 2302 a. A similar effect can beexpected if the magnesium oxide protective layer 251 is arrangeduniformly across an area extending from the positions shown in FIG. 10to an area corresponding to the discharge gap D₁.

Furthermore, the sixth embodiment is explained based on the firstembodiment, but it may also be based on any of the other embodiments.

The above explanation referred to the first to sixth embodiments, butthe present invention need not be limited to a method in which displayelectrodes include projections formed of transparent electrode material,and bus lines formed of metal. In other words, both may be made from thesame material. This simplifies the manufacturing process, and isparticularly valuable when manufacturing the intricate displayelectrodes required for a high definition PDP. To be specific, thedisplay electrodes should preferably be made entirely of metal. In thiscase, a material formed mainly of Ag is ideal, but Cr—Cu—Cr or similarmay also be used. The resistance value of the display electrodes can belowered further if they are made mainly of Ag than if they are made ofCr—Cu—Cr.

Experiments performed by the inventors clearly show that when displayelectrodes are formed mainly from Ag, the reflection coefficient ofdischarge emission reflected by the display electrodes ranges from 80%to a maximum of 95% or more. Therefore, even if light generated insidethe cells strikes the display electrodes, most of this light will bereturned to the inside of the cell without being extinguished (thisholds true even if the discharge emission is reflected three or fourtimes). As a result, discharge generated by the display electrodescontributes to an efficient light display without having an adverseeffect on the cell aperture ratio. Note that the transmissioncoefficient for visible light when using conventional transparentelectrodes of the prior art is confined to a value of around 80% orless, and thus obtaining the superior discharge efficiency of thepresent invention is difficult.

The present invention may further perform black matrix processing on thedisplay electrodes.

FIG. 11 shows an aerial view of the display electrodes in the firstembodiment seen from in front of the PDP. Black matrix processinginvolves forming black layers 2205 and 2305 using a black material,being a metal including a metal oxide or Ag at positions on the frontglass substrate where the transparent electrodes are to be formed,before forming the display electrodes.

By performing such black matrix processing, visible light admitted intothe display from the outside will be prevented from reflecting off thedisplay electrodes 22 and 23 when the PDP is driven during the dischargesustain period. This enables a display with visibility markedly superiorto the prior art to be achieved.

Note, that here an example in which black matrix processing is appliedto display electrodes 22 and 23 in the first embodiment is described,but in the present invention, black matrix processing may also beapplied to display electrodes having a different shape, and to displayelectrodes formed solely from metal.

2. PDP Manufacturing Method

The following is an explanation of one example of a manufacturing methodused to manufacture the PDP described in the above embodiments.

2.1 Manufacture of Front Substrate

Display electrodes are manufactured on the surface of a front glassplate formed of a 2.6 mm thick soda lime glass plate. This is performedby first forming transparent electrodes using photoetching as follows.

A photoresist (for example, a resin that hardens when exposed toultraviolet light) with a thickness of 0.5 μm is applied to the entiretop surface of the front glass plate. Then, a photo mask having acertain pattern is placed on top of the photoresist, and ultravioletlight applied. The front glass plate is immersed in a developer, and theparts of the resin that have not been hardened are washed away. Next,ITO or similar is applied to the gaps in the photoresist on the frontglass panel using a chemical vapor deposition (CVD) method. Followingthis, the photoresist is eliminated by a cleaning solvent to obtain thetransparent electrodes.

Next, bus lines with a thickness of 4 μm are formed on top of thetransparent electrodes from a metal with Ag or Cr—Cu—Cr as its maincomponent. If Ag is used, this is performed by screen printing, and ifCr—Cu—Cr is used, by a vapor deposition or spattering method.

Note that display electrodes manufactured from a metal with Ag or thelike as its main component may be manufactured simply by using the abovedescribed photoetching.

Next, the entire surface of the front glass plate including the tops ofthe display electrodes is coated with a lead glass paste to a thicknessof 15 to 45 μm, and baked to form a dielectric layer.

Following this, a protective layer 0.3 to 0.6 μm thick is formed on thesurface of the dielectric layer using a vapor deposition method, CVD orsimilar. The protective layer is basically formed using magnesium oxide(MgO), but when parts of the protective layer use a different substance,as for example when a distinction is made between the use of MgO andaluminum (Al₂O₃), the protective layer is formed by patterning using anappropriate metal mask.

This completes the manufacture of the front substrate.

2-2. Manufacture of Back Substrate

The surface of a back glass plate formed of a 2.6 mm soda lime glassplate is coated with a conductive material having Ag as its maincomponent, stripes being formed at regular intervals using screenprinting. These stripes are address electrodes having a thickness of 5μm. Here, the manufactured PDP is a 40 inch NTSC (National TelevisionSystem Committee) or VGA (Video Graphics Array) standard model, soneighboring address electrodes are set at intervals of no more than 0.4mm apart.

Following this, a lead glass paste is coated at a thickness of 20 to 30μm over the entire surface of the back glass plate on which the addresselectrodes have been formed, and then baked to form a dielectric film.

Next, barrier ribs approximately 60 to 100 μm high are formed on top ofthe dielectric film in the gaps between neighboring address electrodes,using the same lead glass material. These barrier ribs are formed, forexample, by performing screen printing repeatedly using the lead glassmaterial, and then baking the result.

Once the barrier ribs have been formed, phosphor inks, each includingphosphors in one of the three colors red, green and blue, are applied tothe surfaces of the barrier ribs and to the surface of the dielectriclayer exposed between the barrier ribs, and then dried and baked to formphosphor layers.

Examples of the phosphors conventionally used in PDPs are describedbelow.

Red phosphor: (Y_(x)Gd_(1−x))BO₃:Eu³⁺

Green phosphor: Zn₂SiO₄:Mn

Blue phosphor: BaMgAl₁₀O₁₇:Eu³⁺

(or BaMgAl₁₄O₂₃:Eu³⁺)

Powder with an average particle size of, for example, 3 μm is used foreach phosphor. A variety of methods may be used to apply the phosphorink, but here a meniscus method wellknown in the art is used. In thismethod phosphor ink is squirted from a fine nozzle by forming a meniscus(bridge using surface tension). The method is ideal for coating thetarget area uniformly with phosphor ink. However, the present inventionneed not of course be limited to this method, and another method such asscreen printing may also be used.

This completes the manufacture of the back substrate.

Note that the front and back glass plates are described as being madefrom soda lime glass, but this is just one example of a material whichmay be used.

2-3 Finishing of PDP

The manufactured front and back substrates are sealed together usingsealing glass. Then, the discharge spaces are exhausted to form a highvacuum of around 1.1×10⁻⁴ Pa, and filled with a discharge gas such as anNe—Xe mixture, a He—Ne—Xe mixture or a He—Ne—Xe—Ar mixture at aspecified pressure (here 2.7×10⁵ Pa).

Note that experiments have shown that setting pressure at a range ofbetween 1.1×10⁵ Pa and 5.3×10⁵ Pa when the gas is introduced improvesluminous efficiency (this technique is described in more detail inJapanese Patent H9-141954).

3. Other Considerations

Each of the first to sixth embodiments describes an example in whichtransparent electrodes 220 and 230 are formed symmetrically on a pair ofdisplay electrodes 22 and 23, but the transparent electrodes 220 and 230need not necessarily be formed symmetrically. Instead, only one of thetransparent electrodes 220 and 230 need be provided with the innerprojections 2202 a and 2302 a, and the connectors 2203 and 2302 b. Inaddition, one of a pair of display electrodes may be formed of a metalelectrode (in other words be only a bus line), and the other from atransparent electrode and a bus line.

Furthermore, the first to sixth embodiments describe an example in whichinner projections 2202 a and 2302 a are arranged facing each other inthe y direction, but the present invention need not be limited to thisstructure, and the inner projections 2202 a and 2302 a may be arrangedin positions that are slightly out of line along the x direction.

Furthermore, the pitch at which the inner projections 2202 a and 2302 aare arranged in the x direction may vary for each pair of transparentelectrodes 220 and 230. However, keeping the pitch of the innerprojections 2202 a and 2302 a uniform is thought to enable a uniformdischarge to be generated in each cell, and so this is preferable.

The second to fourth embodiments describe examples in which outerprojections 2202 b and 2302 b are provided, but these need not beprovided.

Furthermore, the outer projections 2202 b and 2302 b may be provided ononly one of the transparent electrodes 220 and 230.

In addition, the outer projections 2202 b and 2302 b are described asforming one whole with the inner projections 2202 a and 2302 a, and arecollectively referred to as the projections 2202 and 2303, but the outerprojections 2202 b and 2302 b may be formed separately from the innerprojections 2202 a and 2302 a.

Furthermore, the inner projections 2202 a and 2302 a, and the outerprojections 2202 b and 2302 b need not be provided in equal numbers, andtheir relative size may also be changed as appropriate.

Furthermore, provision of the connectors need not be limited to theinner projections 2202 a and 2302 a, and they may also be provided forthe outer projections 2202 b and 2302 b.

Furthermore, the connectors 2203 a . . . need not be limited to thenumbers described in the first to sixth embodiments, and the numberprovided may be adjusted as appropriate. However, in this case, too manyconnectors may lead to accumulation of excess charge, and so care needsto be taken so as not to destroy the advantage gained over conventionaltransparent electrodes.

Furthermore, the shape of the apertures need not be limited to arectangle (or square), but may be another shape. Furthermore, the innerprojections 2202 a and 2302 a and the outer projections 2202 b and 2302b need not be orthogonal to the bus lines, and may be slanted at anangle.

The first to sixth embodiments describe an example in which the presentinvention is used in a gas discharge panel (PDP). However, theapplication of the present invention is not limited to gas dischargepanels, and it may also be used in other devices (gas dischargedevices). One example of such a gas discharge device is shown in FIG.12. A gas discharge device 400 shown in FIG. 12A has a structure inwhich discharge electrodes (display electrodes) 422 and 423 (Y electrode422 and X electrode 423) are arranged on a plate 401, and both surfacesof the plate 401 are enclosed by glass covers 401 a and 401 b having aconcave shape. The glass covers 401 a and 401 b are brought into closecontact, and discharge gas introduced in the space between them. Thedisplay electrodes 422 and 423 each have a plurality of rake-likeelectrode lines 4220 and 4230, which are arranged in an interlockingpattern on the surface of the plate 401. These electrode lines 4220 and4230 form the main part of the electrode (or the bus line), and innerprojections 2202 a and 2302 a, outer projections 2202 b and 2302 b andthe like are arranged as appropriate. The present invention may beapplied to the display electrodes 422 and 423 in a gas discharge devicesuch as this one.

Furthermore, the black matrix processing described above may beperformed on the display electrodes 422 and 423 in the gas dischargedevice 400.

Industrial Applicability

The gas discharge display apparatus and manufacturing method thereof inthe present invention are to be used mainly for high definition PDPs andthe manufacture thereof.

What is claimed is:
 1. A gas discharge display apparatus, in which aplurality of cells filled with a discharge gas are arranged in a matrixpattern in a space between first and second substrates placed inopposition to each other, at least one pair of display electrodes beingarranged on a surface of the first substrate facing the second substrateso as to span the plurality of cells, each pair of display electrodescomprising: two extension parts that extend lengthwise along the matrix;a plurality of inner projections electrically connected to eachextension part, and protruding toward the other extension part; and atleast two connectors arranged, keeping a fixed interval therebetween,between the two extension parts, each connector electrically connectingat least two inner projections provided for a same extension part. 2.The gas discharge display apparatus of claim 1, wherein the gasdischarge display apparatus is a plasma display panel.
 3. The gasdischarge display apparatus of claim 1, wherein a same extension part isprovided with a plurality of connectors so as to electrically connectthe at least two inner projections provided for the same extension part,thereby forming aperture array patterns, each having a plurality ofapertures formed lengthwise along each extension part in the pair ofdisplay electrodes, aperture array patterns being formed in at least tworows extending widthwise from each extension part.
 4. The gas dischargedisplay apparatus of claim 1, wherein each connector is a strip arrangedin parallel with the extension parts.
 5. The gas discharge displayapparatus of claim 3, wherein a size of the plurality of aperturesprovided for each extension part varies for each aperture array pattern.6. The gas discharge display apparatus of claim 5, wherein the size ofthe plurality of apertures provided for each extension part becomeslarger for array patterns further away from a minimum gap between thepair of display electrodes.
 7. The gas discharge display apparatus ofclaim 3, wherein each of the aperture array patterns provided for a sameextension part has a different pitch.
 8. The gas discharge displayapparatus of claim 7, wherein aperture array patterns provided for asame extension part that are further from the minimum gap between thepair of display electrodes have a narrower pitch.
 9. The gas dischargedisplay apparatus of claim 1, wherein ends of the at least two innerprojections provided for each of the two extension parts areelectrically connected by a connector, and a gap between the connectorsprovided for the extension parts is the minimum gap between the pair ofdisplay electrodes.
 10. The gas discharge display apparatus of claim 1,wherein one or more outer projections are arranged transversely so as toprotrude from at least one of the two extension parts on a side facingaway from the other extension part.
 11. The gas discharge displayapparatus of claim 1, wherein the extension parts are bus lines formedof metal, and the inner projections are formed of a transparentelectrode material.
 12. The gas discharge display apparatus of claim 11,wherein the bus lines are formed mainly of Ag.
 13. The gas dischargedisplay apparatus of claim 1, wherein the at least one pair of displayelectrodes is formed mainly of Ag.
 14. The gas discharge displayapparatus of claim 1, wherein, when a discharge gas pressure is P and adischarge gap d, and a relation between product Pd and discharge firingvoltage is shown by a Paschen curve, a minimum gap between the pair ofdisplay electrodes corresponds to a gap at a minimum discharge firingvoltage or a vicinity thereof.
 15. The gas discharge display apparatusof claim 1, wherein a black layer forming a black matrix thatcorresponds to a pattern formed by the at least one pair of displayelectrodes is arranged between the at least one pair of displayelectrodes and the first substrate on which the at least one pair ofdisplay electrodes are formed.
 16. The gas discharge display apparatusof claim 15, wherein the black layer forming the black matrix is formedof a metal that includes one of a metal oxide and Ag.
 17. A gasdischarge display apparatus, in which at least one pair of dischargeelectrodes is arranged facing a discharge space filled with dischargegas, the gas discharge display apparatus emitting light when a dischargeis generated between each pair of discharge electrodes by supplyingelectricity to the at least one pair of discharge electrodes, each pairof discharge electrodes comprising: two extension parts that extend in asame direction; a plurality of inner projections electrically connectedto each extension part, and protruding toward the other extension part;and at least two connectors arranged, keeping a fixed intervaltherebetween, between the two extension parts, each connectorelectrically connecting at least two inner projections provided for asame extension part.
 18. The gas discharge display apparatus of claim17, wherein a same extension part is provided with a plurality ofconnectors so as to electrically connect the at least two innerprojections provided for the same extension part, thereby formingaperture array patterns, each having a plurality of apertures formedlengthwise along each extension part in the pair of dischargeelectrodes, aperture array patterns being formed in at least two rowsextending widthwise from each extension part.
 19. The gas dischargedisplay apparatus of claim 17, wherein each connector is a striparranged in parallel with the extension parts.
 20. The gas dischargedisplay apparatus of claim 17, wherein ends of the at least two innerprojections provided for each of the two extension parts areelectrically connected by a connector, and a gap between the connectorsprovided for the extension parts is the minimum gap between the pair ofdischarge electrodes.
 21. The gas discharge display apparatus of claim17, wherein one or more outer projections are arranged transversely soas to protrude from at least one of the two extension parts on a sidefacing away from the other extension part.
 22. The gas discharge displayapparatus of claim 17, wherein, when a discharge gas pressure is P and adischarge gap d, and a relation between product Pd and discharge firingvoltage is shown by a Paschen curve, a minimum gap between the pair ofdischarge electrodes corresponds to a gap at a minimum discharge firingvoltage or a vicinity thereof.
 23. The gas discharge display apparatusof claim 1, wherein a black layer forming a black matrix thatcorresponds to a pattern formed by the at least one pair of dischargeelectrodes is arranged on at least one part of a surface of the at leastone pair of discharge electrodes.
 24. The gas discharge displayapparatus of claim 23, wherein the black layer forming the black matrixis formed of a metal that includes one of a metal oxide and Ag.
 25. Agas discharge display apparatus manufacturing method including, in thestated order, a first step of arranging at least one pair of displayelectrodes across a surface of a first substrate, and a second step ofplacing the surface of the first substrate on which the at least onepair of display electrodes are arranged in opposition to a surface of asecond substrate, with a plurality of barrier ribs interposedtherebetween, areas where pairs of display electrodes intersect withgaps between neighboring barrier ribs forming cells for alight-producing display, the first step comprising, to form a pair ofdisplay electrodes: a bus line arranging step of arranging two buslines; a projection arranging step of arranging a plurality of innerprojections electrically connected to each bus line and protrudingtoward the other bus line; and a connector arranging step of arranging,keeping a fixed interval therebetween, at least two connectors betweenthe two extension parts, each connector electrically connecting at leasttwo inner projections provided for a same extension part.
 26. The gasdischarge display apparatus manufacturing method of claim 25, wherein aplasma display panel is manufactured by arranging the bus lines so as toextend lengthwise in the first step, and arranging cells in rows andcolumns to form a matrix pattern in the second step.
 27. The gasdischarge display apparatus manufacturing method of claim 25, wherein,in the connector arranging step, a same bus line is provided with aplurality of connectors so as to electrically connect the at least twoinner projections provided for the same bus line, thereby formingaperture array patterns, each having a plurality of apertures formedalong a length of each bus line in the pair of display electrodes,aperture array patterns being formed in at least two rows extendingwidthwise from each extension part.
 28. The gas discharge displayapparatus manufacturing method of claim 25, wherein in the connectorarranging step, each connector is a strip arranged in parallel with thebus lines.
 29. The gas discharge display apparatus manufacturing methodof claim 27, wherein in the first step, a plurality of connectors and aplurality of inner projections are arranged so that a size of theplurality of apertures provided for each bus line varies for eachaperture array pattern.
 30. The gas discharge display apparatusmanufacturing method of claim 29, wherein in the first step, a pluralityof connectors and a plurality of inner projections are arranged so thatthe size of the plurality of apertures provided for each bus linebecomes larger for array patterns further away from a minimum gapbetween the pair of display electrodes.
 31. The gas discharge displayapparatus manufacturing method of claim 27, wherein in the first step, aplurality of connectors and a plurality of inner projections arearranged so that each of the aperture array patterns provided for a samebus line has a different pitch.
 32. The gas discharge display apparatusmanufacturing method of claim 25, wherein in the first step, a pluralityof connectors and a plurality of inner projections are arranged so thataperture array patterns for a same bus line further from the minimum gapbetween the pair of display electrodes have a narrower pitch.
 33. Thegas discharge display apparatus manufacturing method of claim 25,wherein in the first step, a gap between the pair of display electrodesis set so that ends of the at least two inner projections provided foreach of the two bus lines are electrically connected by a connector, anda gap between the connectors provided for the bus lines is the minimumgap between the pair of display electrodes.
 34. The gas dischargedisplay apparatus manufacturing method of claim 26, wherein in the firststep one or more outer projections are arranged parallel with a matrixcolumn so as to protrude from at least one of the two bus lines on aside facing away from the other bus line.
 35. The gas discharge displayapparatus manufacturing method of claim 25, wherein in the first step,the bus lines are manufactured from metal, and in the projectionarranging step, the projections are manufactured from a transparentelectrode material.
 36. The gas discharge display apparatusmanufacturing method of claim 25, wherein a layer forming step isinterposed between the first step and the second step, the layer formingstep forming a layer on the surface of the first substrate so as tocover the at least one pair of display electrodes, an area of the layercorresponding to a minimum gap between a pair of display electrodesbeing manufactured from magnesium oxide, and a remaining area of thelayer being manufactured from a material that has a lower electronemission yield than magnesium oxide.
 37. The gas discharge displayapparatus manufacturing method of claim 26, wherein in the layer formingstep, the material with the lower electron emission yield is aluminum.38. The gas discharge display apparatus manufacturing method of claim25, wherein in the first step, when a discharge gas pressure is P and adischarge gap d, and a relation between product Pd and discharge firingvoltage is shown by a Paschen curve, a minimum gap between the pair ofdisplay electrodes corresponds to a gap at a minimum discharge firingvoltage or a vicinity thereof.
 39. The gas discharge display apparatusmanufacturing method of claim 25, wherein the first step includes ablack layer arranging step of arranging, between the at least one pairof display electrodes and the first substrate on which the at least onepair of display electrodes are formed, a black layer for forming a blackmatrix that corresponds to a pattern formed by the at least one pair ofdisplay electrodes.
 40. The gas discharge display apparatusmanufacturing method of claim 39, wherein in the black layer arrangingstep, the black layer for the black matrix is formed of a metal thatincludes one of a metal oxide and Ag.
 41. A display apparatuscomprising: a first substrate with a plurality of display electrodes; afirst display electrode coupled to the first substrate; a second displayelectrode coupled to the first substrate and substantially parallel withthe first display electrode; the first display electrode including anextension part that extend lengthwise and substantially parallel to thesecond display electrode, a plurality of inner projections electricallyconnected to the extension part, and protruding toward the seconddisplay electrode, and a plurality of connectors electrically connectingtwo or more inner projections.
 42. The display apparatus of claim 41wherein the display apparatus is a gas discharge display apparatus inwhich a plurality of cells filled with a discharge gas are arranged in amatrix configuration and the first and second display electrodes span aplurality of cells, the cells having a cell pitch and the plurality ofinner projections being substantially evenly spaced a distance smallerthan the cell pitch.
 43. The display apparatus of claim 41 wherein theplurality of inner projections extend in the same direction and areelectrically connected to the extension part at a first end, andconnected to the connectors at a second end.